<html>

<head>
    <meta charset="utf-8" />
    <title>这是标题</title>
    <style>
        span {
            /* font-size: xx-large;
            font-size: 20px;
            */
            /* font-size: larger; */
            /* font-size: 80%; */
            font-size: 1.2em;
        }

        p {
            font-size: 20px;
        }
    </style>
</head>



<body>
    <p>
        段落
        <span>行内</span>
        段落
    </p>
</body>

</html>